[PATCH net] nfp: correct desc type when header dma len is 4096

[PATCH net] nfp: correct desc type when header dma len is 4096

[Simon Horman]

From: Yinjun Zhang <yinjun.zhang@corigine.com>

When there's only one buffer to dma and its length is 4096, then
only one data descriptor is needed to carry it according to current
descriptor definition. So the descriptor type should be `simple`
instead of `gather`, the latter requires more than one descriptor,
otherwise it'll be dropped by application firmware.

Fixes: c10d12e3dce8 ("nfp: add support for NFDK data path")
Fixes: d9d950490a0a ("nfp: nfdk: implement xdp tx path for NFDK")
Signed-off-by: Yinjun Zhang <yinjun.zhang@corigine.com>
Reviewed-by: Richard Donkin <richard.donkin@corigine.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund@corigine.com>
Signed-off-by: Simon Horman <simon.horman@corigine.com>
---
 drivers/net/ethernet/netronome/nfp/nfdk/dp.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/netronome/nfp/nfdk/dp.c b/drivers/net/ethernet/netronome/nfp/nfdk/dp.c
index 2b427d8ccb2f..ccacb6ab6c39 100644
--- a/drivers/net/ethernet/netronome/nfp/nfdk/dp.c
+++ b/drivers/net/ethernet/netronome/nfp/nfdk/dp.c
@@ -282,7 +282,7 @@ netdev_tx_t nfp_nfdk_tx(struct sk_buff *skb, struct net_device *netdev)
 	dma_len = skb_headlen(skb);
 	if (skb_is_gso(skb))
 		type = NFDK_DESC_TX_TYPE_TSO;
-	else if (!nr_frags && dma_len < NFDK_TX_MAX_DATA_PER_HEAD)
+	else if (!nr_frags && dma_len <= NFDK_TX_MAX_DATA_PER_HEAD)
 		type = NFDK_DESC_TX_TYPE_SIMPLE;
 	else
 		type = NFDK_DESC_TX_TYPE_GATHER;
@@ -927,7 +927,7 @@ nfp_nfdk_tx_xdp_buf(struct nfp_net_dp *dp, struct nfp_net_rx_ring *rx_ring,
 	dma_len = pkt_len;
 	dma_addr = rxbuf->dma_addr + dma_off;
 
-	if (dma_len < NFDK_TX_MAX_DATA_PER_HEAD)
+	if (dma_len <= NFDK_TX_MAX_DATA_PER_HEAD)
 		type = NFDK_DESC_TX_TYPE_SIMPLE;
 	else
 		type = NFDK_DESC_TX_TYPE_GATHER;
@@ -1325,7 +1325,7 @@ nfp_nfdk_ctrl_tx_one(struct nfp_net *nn, struct nfp_net_r_vector *r_vec,
 	txbuf = &tx_ring->ktxbufs[wr_idx];
 
 	dma_len = skb_headlen(skb);
-	if (dma_len < NFDK_TX_MAX_DATA_PER_HEAD)
+	if (dma_len <= NFDK_TX_MAX_DATA_PER_HEAD)
 		type = NFDK_DESC_TX_TYPE_SIMPLE;
 	else
 		type = NFDK_DESC_TX_TYPE_GATHER;
-- 
2.30.2

Re: [PATCH net] nfp: correct desc type when header dma len is 4096

[Leon Romanovsky]

On Fri, Dec 02, 2022 at 02:46:46PM +0100, Simon Horman wrote:
> From: Yinjun Zhang <yinjun.zhang@corigine.com>
> 
> When there's only one buffer to dma and its length is 4096, then
> only one data descriptor is needed to carry it according to current
> descriptor definition. So the descriptor type should be `simple`
> instead of `gather`, the latter requires more than one descriptor,
> otherwise it'll be dropped by application firmware.
> 
> Fixes: c10d12e3dce8 ("nfp: add support for NFDK data path")
> Fixes: d9d950490a0a ("nfp: nfdk: implement xdp tx path for NFDK")
> Signed-off-by: Yinjun Zhang <yinjun.zhang@corigine.com>
> Reviewed-by: Richard Donkin <richard.donkin@corigine.com>
> Reviewed-by: Niklas Söderlund <niklas.soderlund@corigine.com>
> Signed-off-by: Simon Horman <simon.horman@corigine.com>
> ---
>  drivers/net/ethernet/netronome/nfp/nfdk/dp.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 

Thanks,
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>

Re: [PATCH net] nfp: correct desc type when header dma len is 4096

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net.git (master)
by Jakub Kicinski <kuba@kernel.org>:

On Fri,  2 Dec 2022 14:46:46 +0100 you wrote:
> From: Yinjun Zhang <yinjun.zhang@corigine.com>
> 
> When there's only one buffer to dma and its length is 4096, then
> only one data descriptor is needed to carry it according to current
> descriptor definition. So the descriptor type should be `simple`
> instead of `gather`, the latter requires more than one descriptor,
> otherwise it'll be dropped by application firmware.
> 
> [...]

Here is the summary with links:
  - [net] nfp: correct desc type when header dma len is 4096
    https://git.kernel.org/netdev/net/c/5c306de8f787

You are awesome, thank you!
-- 
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html